1. Field of the Invention
The present invention relates generally to network computing and, more particularly, to a virtual display architecture for thin-client network computing.
2. Description of Related Art
In the last two decades, the centralized computing model of mainframe computing has shifted toward the more distributed model of desktop computing. However, as these personal desktop computers become prevalent in today's large corporate and government organizations, the total cost of owning and maintaining them is becoming unmanageable.
The use of mobile laptops and handheld devices to store and process information poses additional administration and security issues. These devices often contain sensitive data that must be carefully secured, yet the devices themselves often travel in insecure environments where they can be easily damaged, lost, or stolen. This management and security problem is particularly important for the medical community, given the increasing use of computing in medicine, the urgent need to comply with HIPAA regulations, and the significant privacy consequences for lost patient data.
Thin-client computing offers a solution to the rising management complexity and security hazards of the current computing model by leveraging continued improvements in network bandwidth, cost, and ubiquity to return to a more centralized, secure, and easier-to-manage computing strategy. A thin-client computing system includes a server and a client that communicate over a network using a virtual display protocol. The protocol allows graphical displays to be virtualized and served across a network to a client device, while application logic is executed on the server. Using the virtual display protocol, the client transmits user input to the server, and the server returns screen updates of the user interface of the applications to the client.
The thin-client approach offers several significant advantages over traditional desktop computing. Clients can be essentially stateless appliances that do not need to be backed up or restored, require little maintenance or upgrades, and generally do not store any sensitive data that can be lost or stolen. Mobile users can access the server from generally any client and obtain the same persistent, personalized computing environment. Server resources can be physically secured in protected data centers and centrally administered, with all the attendant benefits of easier maintenance and cheaper upgrades. Computing resources can be consolidated and shared across many users, resulting in more effective utilization of computing hardware.
The remote display functionality used in thin client computing systems to decouple display from application execution over a network enables remote users to travel and access their full desktop computing environment from generally anywhere. Applications written for one platform can be generally remotely displayed on a completely different one without rewrite. Scientists, e.g., can gain full access at their desktops to specialized computer-controlled scientific instrumentation located at remote locations. Since display output can be arbitrarily redirected and multiplexed over the network, screen sharing among multiple clients becomes possible. Thus, groups of users distributed over large geographical locations can seamlessly collaborate using a single shared computing session. Furthermore, by mirroring local display output and redirecting it over the network, quick technical support can be provided with the ability to see what the user sees on the desktop, enabling problems to be diagnosed and corrected more quickly. In addition, virtualized computing infrastructure such as virtual machines can leverage remote display systems to avoid display device dependencies, further decoupling their execution from underlying hardware.
However, thin-client computing faces a number of technical challenges before it can achieve mass acceptance. One challenge is to provide a high fidelity visual and interactive experience for end users across the vast spectrum of graphical and multimedia applications commonly found on the computing desktop. While previous thin-client approaches have focused on supporting office productivity tools in local area network (LAN) environments and reducing data transfer for low bandwidth links such as ISDN and modem lines, they do not effectively support more display-intensive applications such as multimedia video, and they are not designed to operate effectively in higher latency wide area network (WAN) environments. WAN performance is particularly important given the growing number of thin-client application service providers (ASPs) attempting to provide desktop computing services over the Internet.